The 360 version of GTA V comes on two DVDs. One is an 8GB "install disc" that you must install, and a second one is a "play disc" that you use to play the game. (The PS3 version comes on a single Blu-Ray.) As you can see in this video up top from Digital Foundry, the 360 version with the play disc installed to the hard drive is noticeably laggy compared to the off-disc version. It's not a huge deal, but the lag is present.

Fortunately, the same folks at Digital Foundry have already found a solution: If you want to play GTA V on Xbox 360 without the noise of a spinning DVD, install the first disc on your 360 hard drive like you normally would, then install the play disc to a USB thumb drive. They're sure to point out that your your mileage may vary depending on your thumb drive, but say that the approach made their lag problems go away.